Sweet cravings explained?

Scientists say that they have found a gene that makes some people have a 'sweet tooth'. In two separate studies, scientists at Harvard Medical School and the Mount Sinai School of Medicine in New York have discovered a gene in mice which they believe is responsible for tasting sweetness. They then used the map of the human genome to locate the equivalent gene in humans.

Both studies compared so-called 'tasting' and 'non-tasting' mice - ones that preferred to drink sweetened water and ones that showed no preference. They then examined differences in their genetic make-up to locate the sweet receptor gene. Knowing that mice and humans are genetically similar, they then located the gene T1R3 as a gene likely to have the same effect in humans.

The scientists hope to prove that the T1R3 gene is actually the sweet tooth gene. Robert Margolskee, head of the Mount Sinai team said that if the finding is proven, it could help scientists develop new artificial sweeteners. It is also thought that examining genetic differences among people could have implications for diet and diet-related diseases such as diabetes.

Further experiments on mice will be needed to prove that the gene found is correctly identified, including implanting the mouse equivalent of the gene into non-tasting mice to see if they develop a preference for sweetened water.